Episode 163: Guest Stewart Umphrey on Natural Kinds (Part Two)

0:00 Mark: So let's refresh ourselves why we were talking about continuants as a prelude to talking about natural kinds, which is of course the big topic of the book. Is it that any natural kind, we have reason to believe that it will be a collection of continuants, you know, so squirrel is a natural kind as opposed to water?

0:16 Stuart: Yeah. I'd like to step back just a little bit first. There's an agreement among philosophers of science, philosophers more generally, that if one wishes to discover what a natural kind is or what natural kinds there are, one should proceed in a naturalistic way that would be distinguished from a way that's merely logical or merely conceptual, or merely verbal. And I agree with that. But it seems to me there are principally two ways of proceeding in a naturalistic manner. One is to immediately go to what the natural sciences tell us and take as hypotheses, at least whatever they say natural kinds are, or natural classes or natural types.

The other way is the way that I take it starts from our pre philosophical and pre scientific understanding of the world. And I prefer this latter way partly because it does seem to me that the concept of the natural kind belongs to pre philosophical and pre scientific thought, even if the term itself is rather technical. And the other is because in the 19th century the term natural kind was introduced by John Venn. This is the latter half of the 19th century. He was following John Stuart Mill, what Mill called a real kind, John Venn calls a natural kind.

And both of them give as their examples such things as animals and plants and phosphorus and sulfur and water and the like. It seems to me that this is the preferable way to go because it's more in keeping with with the way the concept is first of all used. And if one takes this way, it does appear that there is such a thing as the concept of a natural kind. And it's the type or class whose members or instances are continuants which belong to that class or exemplify that type in virtue of their natures. And water is a hard case. This means that such things as, let's say, electric charge isn't going to count as a natural kind, even though if one looks at a physical science, it most certainly seems to be a natural type having many instances.

It's a fact that the philosophers of science who have taken this other naturalistic way of looking to the natural sciences have all tended to conclude that there is no such thing as the concept of the natural kind. The theoretical interests of natural scientists are simply so varied, there's no way of seeing any unity there. The only thing they have in common is they're all of the natural world.

3:21 Dylan: So in this respect, one part of your book is trying to clarify what one would mean by a natural kind and say, is such a concept intelligible as a natural kind? And to that you come down, yes, it is understandable what you would mean by natural kind, such that you could then go about looking for such a thing.

3:43 Stuart: Right, okay.

3:46 Wes: Or what would be true if there are such things as natural kinds? What would have to be true?

3:51 Stuart: That's right.

3:52 Wes: And it sounds like if they're going to be natural, then they must have a nature. And the continuing part of the thing is really what grounds the nature. And if they're going to be natural kinds, they'd also have to reflect some sort of mind independent reality. And that's where we got the talk of the metaphysics in the Universals in the earlier chapters.

4:13 Stuart: That's right, yep.

4:15 Mark: But just to clarify, so it seems that Blackie was a great example of a continuant. But you might want to argue that, for instance, a particular water molecule is also a continuant, because even though a glass of water is not continuant, but the water molecule, we said it has a nature of being H2O combined in that way, and it can bop around and participate in all sorts of other things. But if it has been sliced, if one of the hydrogens is taken off, then it's not that thing anymore. So it is something that stays the same through changes. So it's not just that continuants are living things. Right.

4:49 Stuart: I think that an H2O molecule, especially a free one, if it's by itself it's not locked up in some more complicated chemical system, that it's a very strong candidate for a continuant. And it would mean that water molecule or H2O molecule is a strong candidate for a natural kind.

5:10 Mark: So that's the method is that we're coming up. It could even be that Blackie as a continuant or squirrel doesn't end up being a natural kind. But we're going to start with what we think intuitively based on this unchanging through change concept is going to be a continuant and try to build natural kinds on those. But it could be that you end up coming up with a concept of natural kind that rules out some of these things that initially were taken even as paradigmatic examples.

5:33 Stuart: Right. Blackie is a very good example of a continuant like object. And in everyday life we take it to be a continuant. But it may turn out that the class of squirrels, what we think of the class of squirrels, is not a good example of a natural kind. And it might be better to say that it's not really a natural kind at all.

5:56 Dylan: A similar example that might make it clear the way in which that could be wrong is a kind of species genus distinction. Right. So that if I said I have my dog and I agree for all the reasons we talked about Blackie, that my dog is a continuant and my dog is a German shepherd. It may be that German shepherd is

6:20 Stuart: not a natural kind.

6:22 Dylan: Natural kind.

6:23 Stuart: Right.

6:23 Dylan: But dog is. But that confusion in the reasons for why a German shepherd is not a natural kind could be the same reasons why dog might not be a natural kind ultimately.

6:34 Stuart: Right. An easier example would be shrub. There are individual plants which in some circumstances will be what we call trees and not shrubs and other circumstances in which they will be shrubs and not trees. So do we want to say that it's both a shrub and a tree, or it's a shrub in circumstances C, but not in circumstances C? Prime. It might be better to say that shrub and tree are not natural kinds. I'm not saying that that's correct. I'm saying that this is the sort of question that we'll want to have.

7:10 Dylan: Yep.

7:11 Mark: And you end up claiming pretty strongly that an entity cannot be an exemplar of two different natural kinds. Are we at the point where you can say why that would be the case, or do we need to build more theoretical apparatus here first for that to make sense?

7:26 Dylan: But we could say what a natural. I mean, we ended with continuants on four and the name of the next chapter is natural kinds.

7:33 Wes: And Stewart did give the definition at the beginning, but we.

7:36 Dylan: That's true.

7:37 Wes: Did you want to restate it?

7:38 Stuart: A natural kind is a class whose members resemble one another in virtue of their natures or essences, or in virtue of instantiating one and the same type of. Or a natural kind is a type whose instances are all and only those continuants which exemplify.

8:03 Mark: So it seems key there that each continuant has only one nature, so we can't say that it is. Blackie is a squirrel, and so he exemplifies squirrelness, but Blackie is also an animal, so he exemplifies animality. And both of those are natural kinds. Why would we not want to admit that as a possibility?

8:22 Stuart: Well, as you start out by saying, for any continuant X it has one nature, nx it has one nature, it doesn't have two natures, and it's in virtue of that nature that it belongs to a natural kind, if indeed it does belong to a natural kind. So the only way you could have it belonging to more than one natural kind is if you have nested natural kinds, let's say species in genera. But I argued in chapter three, the argument was admittedly quick, but I think it's correct, I think it's sound that if a specific universal is real, then the generic universal under which it seems to fall is a well founded concept. It's not itself an entity. Or if what we call the generic universal, the genus, is the real universal, then the specific types under it are well founded concepts, more or less well founded concepts, and not themselves real. And it's because a universal can't be composed of universals.

9:33 Mark: So this seems to say something about what a nature, what an essence is, that it can't be just a set of necessary properties, because then Blackie could represent, you know, some of his necessary properties are the ones that constitute his animality. And so you could say he has an animal nature and therefore Animality is a natural kind that encompasses squirrels and everything else. It's not that squirrels are members of animality. It's not a species genus relationship. No, it's that Blackie as an individual has a nature in virtue of which, you know, if you're just looking at those particular properties that relate to animality, therefore he exemplifies animal.

If you're looking at a wider set of characteristics that he has also necessarily. But if a nature is just a bundle of characteristics, well, then we could point to squirrelness, or once you open that up, then as many different necessary characteristics as he has, you could potentially posit indefinitely many kinds, at least a kind based on each of those characteristics or, you know, permutations, combinations of those.

10:36 Stuart: Yeah, and I don't see anything wrong with that, except we ought to say that at most one of those kind types is real. The rest of them are all concepts or names.

10:47 Wes: And correct me if I'm wrong, but if we're trying to say why Blackie is one entity, it's not going to do us any good to have recourse to saying, well, here are the two natures that explain why Blackie is one thing. Is that the right way to.

11:02 Stuart: That's right.

11:02 Wes: Think of it. Okay.

11:04 Stuart: That's right. There is one modern scientific essentialist, Brian Ellis, who maintains a distinction between kind essence and individual essence. And his claim is that in cases of. This is a somewhat technical subject. Now, in cases of beta decay, an atom which belongs to one kind might decay into an atom of another kind. He wants to claim that there's a kind shift there, but that the individual essence might be the same. And I claim that that can't be true, that if beta decay has taken it from one natural kind to another natural kind, then a substantial change has occurred.

11:49 Dylan: It's a kind transformation.

11:51 Mark: We might, out of convenience, call the free floating water molecule Fred. But if Fred then loses a hydrogen, then we might still want to call him Fred for our convenience. But it's not really the same, Fred.

12:04 Stuart: Yeah, we do this all the time. I think Socrates dies. What are we going to do now with Socrates? People say, but Socrates isn't around anymore. Yes, but it's convenient, maybe more than convenient, to continue calling whatever it is we're looking at at the moment, Socrates.

12:24 Mark: So what are other points from chapter five that we want to make sure we hit here?

12:28 Stuart: Well, two things. One is that while my description of the concept of a natural kind is rather constrained, it doesn't mean that we can't call other kinds natural kinds. But we should bear in mind that we're doing so because there's an analogy between that particular class and a natural kind in the primary sense of the term. So I allow for quite a bit of freedom, actually, in the way we think and talk about things. But still, the concept of a natural kind in the primary sense of the term is, or so I argue, constrained in the way that I've constrained it. The second thing is, I then try to say, on the basis of what I've said so far through that part of chapter five, I take up the more empirical question, whether there are natural kinds. And I claim that our pre scientific and pre philosophical understanding and experience of things just isn't sufficient to answer that question.

13:37 Dylan: And that's. I want to ask why that's true, but I guess the reason being that if there's a place where you would draw the line in the sand with respect to Aristotle, it might be something like this, right?

13:50 Stuart: Yes.

13:50 Dylan: Yeah.

13:51 Stuart: The paradigmatic continuants are such that the differences between kind and kind, kind one and kind two, are usually unclear. There are borderline cases, problematic cases, and that's a reason, not a sufficient reason, but it's a reason for suspecting at least, that the way we've carved up these nature into kinds is somewhat arbitrary. We just decide the line is going to be drawn here.

14:24 Dylan: And also we might even admit that the way in which we do that depends upon a theoretical apparatus that we have, that we acknowledge changes. And some of us might say that it evolves or refines or any other kind of way of saying there's a directionality to it, or that we're getting closer to the truth of the matter, any of those things. But nonetheless, that. That carving up in that theoretical apparatus does influence the way we do that, what we would call kinds.

14:53 Stuart: That's a second reason for being reluctant to say, yes, there are natural kinds. And I think a third reason, and this is sort of intrinsic to the inquiry I present in this book, is that as I've gone on in my inquiry, things have become murkier and murkier. And at a certain point I at least want to say I don't trust my hunches anymore.

15:17 Wes: There's another possibility, which is that if we find out that there are no such things, or at least that we can establish anything in the observable world counts as a natural kind in a strict sense, that natural kinds in the loose sense reflect natural kinds that we just don't know about, and that they're systematically related to them and that they borrow their natural kind likeness from these sort of prototypical natural kinds that cognitively we can't get at. That sounds a little bit Kantian, like sort of an empirical world that's systematically related to a world of things in themselves. But it would explain why there's sort of a being and becoming in the world. There's a murkiness to all this, but theoretically it could be grounded in something non murky to which we don't have real access.

16:06 Stuart: As many philosophers have noted, our pre philosophical, pre scientific understanding of things is to a considerable extent practical or pragmatic. We're dealing with the world, we're trying to survive in it. And we found these ways of typifying and classifying things to be very useful. And it doesn't mean that they're correct.

16:29 Dylan: In fact on that ground in acknowledging that one might be inclined to just say they don't exist. That's in fact the reason for saying there are no natural kinds.

16:39 Stuart: That's right.

16:40 Mark: Well, and you had set up in the previous chapter that just because the edges are blurred in something does not mean that the thing is not at least a conclusive argument for arguing that the thing does not exist. That the fact that for a natural kind there might be some borderline cases. Well, wasn't that the case with a continuant as well, that Blackie like which what counts as his edge is his fur, part of him, the things in his digestive tract, the independent organisms that are operating with him? Or you said that it becomes not Blackie when he dies? Well, is there a sharp moment which it's Blackie then not Blackie or is there's obviously some vagueness and that shouldn't keep us from saying that Blackie is a continuant.

17:19 Stuart: Right. And I was willing to make that move once in chapter four. And then I had to ask myself am I ready to make that move a second time in chapter five with regard to natural kinds? And I don't know what you guys think of this, but I thought once was enough.

17:40 Dylan: Yeah. Blatant in it again is this. These are all dimensions, it seems to me, of the murkiness of the being becoming question.

17:47 Stuart: Yes.

17:47 Dylan: And that way Mark just formulated where exactly that moment is and where those edges are, are going to be there because you have something that has a being that is also constantly becoming.

18:00 Stuart: Yeah. And one of the major claims in my book is that the murkiness which attends continuants spreads as it were, into our understanding of natural kinds. And this Is why not just continuants, but natural kinds have been so problematic for philosophers in the history of philosophy and why they have been tempted to just stay away from them and go to mathematical kinds, let's say.

18:34 Mark: Well, then we should hook this back up to universals, because you were just saying that. Okay, continuant, you could argue that it's going to be fuzzy because of the being in becoming things, it's dying. But squirrelness, insofar as it is an entity, it doesn't seem like that's becoming. Unless you're looking at squirrelness as an evolutionary thing, can we say a species over it's at least it's much less clear what you would mean by that.

18:57 Stuart: Yes. And if it were true that squirrelness or the nature of blacki, the essence of blacki, if it were true that it's a sort of hardcore sort of crystalline heart of the thing, which one could distinguish sharply from its materiality, its involvement in change and in its surroundings, then one could say it's possible in principle to be very clear about these things. But I don't think that the nature or essence of a continuant is a hardcore in that sense.

19:35 Mark: So not only the whole continuant is not a type 3 self contained entity, but its nature itself cannot be a type 3 entity.

19:43 Stuart: I don't think that it's an entity at all. It's the nature of an entity.

19:46 Mark: Okay.

19:47 Stuart: And the problem is, I don't assert this as fact, but this is the way it seems when one investigates this. It seems that there's something inherently problematic about the nature of a continuant. I think Aristotle discovered this. One of Aristotle's expressions for the nature or essence of a thing is the to ti estin. And that's often translated as the what it is. But it could also be translated as a question. It's the what is it? So at the very heart of the thing is this question, as it were. It's what it is is what is it. Of course, that doesn't get us very far.

But if one takes it that way, and I don't say this is the this is the way one should translate this expression, but if one takes it that way, this would be Aristotle's way of marking the fact that there's something inherently problematic about the nature of a continuant or what he called a natural ousia, a natural entity or substance.

20:44 Mark: But you do want to say that there is an entity which is the universal squirrelness. It's just that its relation to the individual squirrel is not through yet another entity, the squirrel's squirrel essence.

20:57 Stuart: Correct.

20:58 Mark: Because that would just stack up entities that you. You mentioned Bradley's regress several times.

21:03 Stuart: Yep.

21:04 Mark: Once you. Entities the connection, then you say, well, what's the connection between the squirrel and its essence? Well, that must be that relation. That's an entity too. And then what connects the squirrel to that relation that's connecting to it becomes an infinite regress.

21:17 Stuart: Yes. And this argument you've just given can be generalized, I believe, and it's one of the most powerful arguments in ontology. Whenever one finds oneself doing that, one should say, stop.

21:30 Wes: No more entities.

21:33 Stuart: Not that many.

21:35 Mark: Well, but so say more than why you want there to be the natural kind itself, which is a funny kind of entity. It's like a Platonic form. It does not exist in space and time. That this is a legitimate thing in the ontology, as opposed to merely, perhaps an objective, you know, in other words, intersubjectively verifiable through phenomenology. But still, it's just a. It's a conceptual thing. It's just something that we use. It's a very. We want to say, given self evidently given naturally, somehow in experience. But couldn't it still be a feature of the collective or individual mind? That is. It's a concept.

22:12 Stuart: Yep.

22:12 Mark: You're saying it's not a concept, it's an entity. Why?

22:14 Stuart: Well, I'm saying that it's possible that it's is okay. We shouldn't discount the possibility. If we do that, then we've taken a position in the perennial debate about the existence of universals. Now I do in fact take a position, but I put it forward as a hypothesis, not as an assertion.

22:36 Mark: And why take a position at all as opposed to being a pragmatist or a skeptic or something, and saying, well, it doesn't really matter whether to count it as an entity or not. It's just a matter of how it directs whether we do science or not. What is at stake in here?

22:49 Stuart: Well, I have very strong skeptical inclinations. It's very easy for me to be very skeptical about just about everything. But in this book I was trying to bracket that and I was trying to present a metaphysical account of natural kinds. But I tried to flag the fact that there's uncertainty about some basic propositions by calling them hypotheses. And this is a difference between my attitude in this book, which I think is a philosophical attitude, and the natural attitude. In the natural attitude, these things are simply taken for granted in the attitude I adopt in this book.

Some suppositions implicit in the natural attitude are accepted, but they're accepted as hypotheses in exactly the same way that a scientific hypothesis is presented. It looks like it might be that way, but it's subject to further revision, correction, and possibly rejection altogether. So one always has to circle back in metaphysics and reconsider these suppositions or hypotheses.

24:00 Mark: I like your insistence several times in the book that even if we find one of these positions in the literature or in common parlance that seems like it captures the phenomena, it's still not ours. We have to earn it in some ways that even if you say, wow, Aristotle's idea of essences, this actually seems to have some good points to it. No, you can't just latch onto that. You have to, in this ongoing philosophical inquiry, somehow make it legitimately yours.

24:29 Stuart: That's right. And this is one of the reasons that I put off a consideration of scientific theory as long as I do, because I want to fully explore this first resource we have before turning to it. It's very tempting for philosophers of science, philosophers of nature, they sometimes call themselves these days to simply take for granted whatever the scientific theory tells them. They haven't done the hard work of securing the theory that they're making use of. They simply take it for granted. And I flag certain suppositions in the natural attitude as hypotheses, because while with respect to some of them I do a little work, I'm not taking any of them for granted as true. It's always possible that they need to be reconsidered, revised, possibly rejected. There's no safety net.

25:25 Dylan: Shall we go over the six and seven a little bit, physical kinds and biological kinds, and at least highlight some of the things that go on in that investigation of scientific theories? Sure, Yep. So, broadly speaking, you, after getting through natural kinds, you then turn to science and look at what it says with the background that you've done and start investigating physical kinds, more or less chemistry and particle physics, and looking for what are putatively the natural kinds there and whether there are good examples of them. And then you do something similar in the biological kinds with both things like speciation and then also genetics.

And then you have a kind of conclusion which I think reflects on both of them regarding emergence that I really want to make sure we get to right at the end. So one of the things you, you mentioned earlier, that is in the list often of natural kinds are things that we referred to earlier as Mass entities, things like iron and sulfur as well as water. And there are reasons for them that would be true, but then reasons that they fail. So we've talked for a while so far that water itself, as the H2O molecule, would be a candidate for a continuant.

And therefore candidate is a natural kind.

26:58 Stuart: Right?

26:59 Dylan: Just thinking about six. Is there more that we should say about that in terms of chemistry before then? I think the thing to move on to is the other candidate would be something like electrons or individual fundamental particles.

27:11 Stuart: Water is a good place to begin. I use water as an example not only because it's a paradigmatic continuant according to our everyday understanding of the world, but also because there's a vast literature on the semantics of the term water and its use in various contexts, which I make some use of. And there is a view it's not so common now, but it was common in the 1980s and 90s put forth first of all by Kripke and Putnam, according to which water is H2O is a statement of the essence of water. And it was discovered empirically. And yet what they discovered, this is a good example of transcending one starting point.

And yet what they discovered was a necessary truth, even though it was discovered by empirical means. This is Kripke's view. I try to show first that if you look to what the chemists say about water, it's much more complicated than that. And the key complication is that while chemists often speak of their subject matter in terms of substances as masses, it's because they're very interested in the chemical properties of bulk things. Their theoretical understanding of all these apparent masses is of them as collections of molecules. And so it would be best just following the theory now, not the pragmatics of chemistry, but chemical theory, to turn to water molecules and these they regard as H2O molecules.

And then our question is, and this follows directly from chapter four on continuants, if indeed these are continuants and chemists speak of them as if they were, then each of them must have a nature or an essence. And so the question is, how are we to describe that essence? And I argue that H2O is a very rough and ready way of describing it, that according to chemical theory, a more accurate way, it's not available to us right now, it's too complicated, but would be some specification of the Schrodinger wave equation for that molecule.

29:41 Dylan: And that would be the candidate, because you would have a description that would allow you to talk about how it changes in itself. It remains a whole and interacts with the world.

29:52 Stuart: Exactly, exactly. It's material. It's composite. It's at least grade two, maybe grade three, but let's say grade two, because we're going to assume it's a continuant for the time being. It's certainly involved in change. If the chemists are right, the quantum chemists in particular. It's changing all the time, and it's indeterminate. Its boundaries are indeterminate. Its shape is indeterminate.

30:19 Dylan: When we say it's indeterminate, yet we would still say it has a shape and it has boundaries in that fuzzy way that Mark was talking about before. Just like Blackie.

30:28 Stuart: It is apparently very well founded to say that it has bonds. There are chemical bonds. And we can quantify the geometrical relationship among these bonds between the oxygen atom and the two hydrogen atoms. The angle is roughly 105 degrees. It can change a little bit in special circumstances, but it's about that. It's not about 130 degrees or 70 degrees, let's say. One thing I would like to add here. Chemists don't talk about the nature of water in this way. No, this is the way that someone would talk about who is interested in an H2O molecule as a continuant.

31:10 Dylan: I haven't interacted with a lot of chemists, but I've interacted with enough scientists and enough physicists to know that they might not say so in a book, but when they talk amongst themselves, they will talk about that. That's just not what X does. So electrons behave like this. And I know that this signal that I have or this other entity, be it a mathematical one or not, is not like that. And all of that language is kind language.

31:43 Stuart: Yes, it is.

31:44 Dylan: And wrapped up in that is both what you're thinking of it as a substance as well as what it is in the way it's changing.

31:54 Stuart: Right.

31:54 Dylan: And if you press them on it very quickly, they'll back away from it and they'll start talking about it not having a substance. Exactly. And it has a kind of interaction with the world. And hopefully we'll talk a little bit more about natural law versus natural kinds. But all that said, that just because they don't say it in their books doesn't mean that they don't actively interact with the world and even in their profession in that way.

32:17 Stuart: Well, I'm happy to hear this because I've talked with many fewer chemists than you have, I'm sure. And this is something I've found too. They will talk this way until I try to pin them down and start using the word essence or something.

32:30 Dylan: Then they start backpedaling.

32:31 Stuart: They get scared immediately, oh, this is metaphysics. That's spooky stuff.

32:36 Mark: So, Dylan, I know you're having to carry some of the heavy weight in here, as Wes and I did not read those two chapters on the practical applications, we both did get to the end. It was interesting that in the epilogue, you are contrasting just through the history of philosophy, how nomological talk, in other words, talk about scientific laws came from a different place than talk about teleology, talk about essences. So it seems like natural kind talk should be teleological talk. So you're explaining why something does what it does because of the sort of entity it is.

But isn't that compatible with talk of. Well, it behaves that way because of the sort of entity it is. And natural laws capture at a higher level, perhaps, the sort of behavior that various entities will engage in, given that they're in certain situations. Say something about the contrast between those two types of talk and as opposed to Aristotelian talk of essences in your new talk of natural kinds. How is that supposed to feed in?

33:36 Stuart: I think this is a serious problem. First of all, it seems to me that you're absolutely right that these two kinds of talk, as you put it, the natural kinds talk and the natural law or law of nature talk, these two kinds come from very different sources and they represent two very different outlooks on the world. And it's a fact, I believe, that the early Galilean scientists, Galileo, Newton, that period, they generally thought that there are natural law, laws of nature, and there are no natural kinds. Why? Because, as Newton said, Descartes said, there are no substantial forms.

34:25 Dylan: Everything's grade three.

34:27 Stuart: Yeah, every material thing is grade three, unless there are metaphysical atoms. And most of these people were not atomists.

34:36 Dylan: In Galileo, you talk about in chapter six, as well as going back to it a bit in the epilogue, Laws of Nature, a great example of something falls at a rate, covers a distance proportional to the time squared of its. That's falling. Galileo's law. And that is going to be true of, in Galileo, of anything that is massive, anything that admits of being affected by gravity.

35:05 Stuart: He almost says this at one point. It doesn't make any difference what's falling.

35:08 Dylan: It doesn't make any difference. And throughout Galileo and Newton, the idea is that we have characteristics of things that have nothing to do with the particular kind of materiality it is. And therefore the kindness is superficial. And in fact, you could even just go so far as to deny things. Things have momentum, things have mass. And the way in which they interact in the world is governed by the amount of quantity of those things that they have. But they don't interact in the world insofar as they have kinds. And there may be other mass like characteristics. Maybe ultimately we get charge or something like that that have those. But those features are not kinds of. They are maybe properties that govern how the individual entities interact in the world, but they themselves aren't kinds and they aren't signals for kinds.

36:05 Stuart: Yeah. In fact, there's a passage in his two New Sciences dialogue in which the context is a discussion of this free fall law. And he says that the law gives us the essence of the motion. Those are the essences he's after.

36:20 Dylan: Yeah. And in fact, we're not too far from this. Like when we say the trajectory of an object thrown through the air as a parabola, we will all acknowledge that in fact it won't be exactly a parabola because there are all kinds of things that deviate from it. But it is essentially a parabola and that's what it is. But it's not a kind, but it is describing its essence. I guess this is what you mean when you say about a deep conflict is that by describing things in terms of laws, we are making another essence claim about the world and about the entities in the world that is in significant tension with a kind description of the world.

37:02 Stuart: Yeah. And this brings us back to something else that mark said. These 17th and 18th century natural philosophers or natural scientists thought that the conflict between these two outlooks was so deep that if you accept one outlook, you have to reject the other. But it seems to me that they aren't logically incompatible. It may be that there are both laws of nature and natural kinds, but natural science gives us a reason for hesitating to say so I wrote something

37:38 Dylan: related to this and we'll have to say more about what emergence is, but I wrote down to myself as doesn't Natural law realism emergence Natural kind realism?

37:49 Stuart: Well, that sounds good to me. That's a good summary of my book.

37:53 Dylan: Okay.

37:56 Stuart: And it happens through. See if you agree to this also. It happens through symmetry breaking. Yeah, okay.

38:03 Dylan: Yeah, but there probably we need to be not merely as specific as symmetry break in as it would be in particle physics. We'd have to be talking about, well,

38:13 Wes: say what you mean by symmetry breaking.

38:15 Dylan: Why don't we say a Little bit more about. Go down a little bit more about these laws of nature questions, right?

38:19 Stuart: Yeah.

38:20 Dylan: One effect. When you start describing the world in terms of laws of nature, you're saying that there are relations that govern the parts. And ultimately in chemistry and particle physics you end up with entities like fields that have maybe individuals in them that seem like that they are. You want to call them real entities, but what's really governing them are universal invariant relations. So you describe them in terms of symmetrical relations, using that phrase symmetrical relations and invariance. They mean almost exactly the same thing.

38:59 Stuart: Right.

38:59 Dylan: That a symmetry reveals an invariance. It things, the consequence of which things are conserved and that they act as the boundaries for the way in which those entities interact. And in fact, it is not going too far to say that entities that behave according to these symmetries and these invariants will fill them up. They will exhibit all the dynamical characteristics that would be allowed in that invariance, but only those.

39:30 Stuart: Right.

39:31 Dylan: And those invariants will turn out not to be strictly true all the time.

39:39 Stuart: Right.

39:40 Dylan: Those invariants will get broken. And so symmetry breaking means that in some way that invariance is not quite true. So formally speaking, in particle physics you have this characteristic where if I go all in with a theory of everything kind of model, and in quantum field theory, I would say that at a certain temperature of the universe, all particles have these inherent symmetries and then as things cool down, they're developed to be asymmetries and invariants that I'm able to make distinguish things from one another that I couldn't before.

40:20 Stuart: Yes. And if I understand it, these symmetry breaking events are spontaneous.

40:24 Dylan: Yes.

40:24 Stuart: They just happen.

40:25 Dylan: They just happen.

40:26 Stuart: There may be other symmetry breaking events farther down the line.

40:30 Dylan: Yes.

40:30 Stuart: Let's say distinguishing living from non living things which are not spontaneous. Not in the same sense.

40:37 Dylan: Yes, in the sense that spontaneous the way radiation might be spontaneous and probabilistic as opposed to spontaneous in the sense of self organizing.

40:48 Stuart: Exactly.

40:49 Dylan: Stewart, when you just described the kind of symmetry breaking event that might be related to the distinguishing between not living and non living things, that's what I meant by generalizing the notion of symmetry breaking over and above a kind of formal. That's right, formal mathematical understanding that you have in saying that if I break SU group theory and I get mass out of the system.

41:16 Stuart: And in particle physics, you used a key term in that account, which I would like to mark. You spoke of symmetry relations and other relations in quantum field theory. In fundamental physics, the Aristotelian Category of relation is primary. In Aristotelian metaphysics, as in his categories in physics, the category of substance is primary. And there's a place, I don't remember where, now maybe one of you does, where Aristotle says the category of relation is most remote from the category of substance. So there's been a kind of inversion that's taken place in the shift from Aristotelian physics to quantum field theory.

42:01 Dylan: But this is emblematic of the distinction between natural kinds talk and natural law talk.

42:07 Stuart: Yes, it is. I don't know if we want to jump all the way to the final section of chapter seven, but everything depends on whether there's been substantial emergence in the course of these events.

42:20 Mark: Yeah, that seems like a good sort of final topic, is to get at what's supposed to be. One of the big upshots of you considering natural kinds is that it actually lets you talk about emergent entities, that there are living entities have some properties over and above what you might predict by looking at their components. And so the scientific dream of being able to reduce all of biology to chemistry and all of chemistry to physics, et cetera, is misguided because of this. There's something about natural kinds that introduces indissoluble complexity.

42:52 Stuart: Yeah. Dylan's in a better position to talk about this than I am. But in my reading of the natural sciences, there's a perennial, very strong tension now between the tendency to reduce everything to fundamental physics and the tendency to reject that. So there are those who claim that a theory of every everything, one word is a theory of everything or there are no things is another way, is a dramatic way of putting it. And the view that a theory of everything is not a theory of everything, very far from it. And this is why natural science has to have all. Why there have to be all these special sciences. Because there's this. There are these natural kinds, and in

43:38 Dylan: fact, in the strong form of that, there are actually interactions and relations amongst the emergent entities that are not a consequence of the underlying lower level interactions.

43:55 Stuart: Yeah. Dependent on, but not consequent.

43:59 Dylan: Dependent on, but not consequentials.

44:01 Stuart: Yeah.

44:01 Dylan: Yeah. I don't know if this is a trite example, but it would be to me, like saying there's no way, even in principle, that an account of particle physics would give an explanation for macroeconomic relations.

44:20 Stuart: Seems true to me.

44:21 Dylan: Yeah, it seems true to the extent that you went so far as to say communities are emergent characteristics of. You wouldn't get those things.

44:31 Stuart: If this is correct, then this is a way of Seeing how it's possible that there could be laws of nature and also natural kinds. And the paradigmatic laws of nature we will find in, for example, quantum field theory. Those are good examples of laws. In biology, we might find good examples of natural kinds. It's much less likely we'll find any good examples of laws of nature. The things that are often called laws can't be mathematized. They seem to be nothing other than generalizations that people have made based on experience. An example I use in the book is Dollo's law. Dollo's law says that species do not recur. If a species has become extinct, it will never come back. So we try to.

45:20 Dylan: No dinosaurs, right?

45:21 Stuart: Yeah, just. I mean, we can compare that with Galileo's law of falling bodies.

45:26 Dylan: Yes.

45:27 Mark: Well, I think we could have a robust theory of natural kinds and still insist that it all reduces to the vale of tears, to the cycle of samsara. Actually, this is just a goofy way of saying, you know, again, we're kind of returning to the beginning of the book. Yep, you argue against any form of idealism, including transcendental Kantian idealism, but it seems like you could say, okay, everything we're talking about here is still the world of experience, broadly construed. And so we can have whatever ontology within that world we want and say, yes, natural kinds actually provide an explanatory role and lets us talk about emergence in a more easy way.

And we should not try to reduce everything to physics. But yet still, this is all in some broader sense. These are truths of the world, of concepts, something like that. And what the world actually is in itself is forever unknowable. You know, it still seems like, you know, that was Kant's big point is you could do as much science as you want, and that still can be sharply separated from metaphysics, from ultimate reality. I mean, is there really any. Anything to say in response to that other than that's not very useful or.

46:34 Stuart: No, it is very useful. I think, in fact, I just don't know if it's true. This is a perfect example of how in philosophy, it's in science too, we have to keep circling back to our hypotheses and considering them again. You're taking us back to my hypothesis H1, that there's a world there which is independent of the way we think and talk about it. Let's look at that hypothesis again. I don't know that it's true. I give reasons for going on, on the hypothesis that it's true. But let's look at it again. Right in chapter two. I give what for me is one of the most powerful examples for thinking that something like transcendental idealism is true.

You look at Aristotelian physics and you look at, let's say, Cartesian physics. One of them admits continuants and natural kinds. That's Aristotle. Descartes admits no such things. He'll still use the word horse or an individual horse, let's say, I don't know, Whitey. And he says of this horse that it is a delimited portion of matter in motion. That's all it is. It's a grade three object and we choose for practical reasons to regard it as unitary. It's useful to us in everyday life and it may even be useful in science. We may like to think of its center of mass in relation to other centers of mass, and so on.

So the question arises. This is a deep metaphysical question. Is Aristotle right or is Descartes right about the world? It's possible both are wrong. But let's say one of them is right. If what one might call transcendental realism is right, only one of them is right. They can't both be right. If what Kant called transcendental idealism is correct, and if one expands upon it modifies a little bit, they could both be right in a sense. And what happened is Aristotle, following common sense, simply chose to regard this and that horse as continuants and chose to regard the kinds to which they belong.

Let's say the species horse as a real species. Descartes rejected that. He decided. He didn't discover. He decided that this or that horse is a delimited portion of matter and motion, and decided that all kind talk is simply pragmatic. It's simply useful. It's for bookkeeping, for ease of understanding one another, and so on. It has no theoretical significance whatsoever. These are both decisions and we don't have to say one of them is correct and the other is incorrect. It's just that one of them was accepted for a while and then the other was accepted for a while.

So what looked like a metaphysical question that no one was able to answer satisfactorily just evaporates. You can deal with a lot of metaphysical problems this way. Does God exist or does God not exist? Well, according to the old time realist, one of those two answers is right. But according to a modification of the Kantian view, well, one was accepted, generally accepted, and then another was accepted, at least by some.

49:49 Dylan: This ends up hearkening back to your skeptical Disposition that you were framed earlier.

49:53 Stuart: Yeah. And you can see how in a skeptical frame of mood, I could really pursue the press apart. Sure.

49:59 Dylan: But that respect, you would end up with a kind of pragmatism that admits of everything being up for grabs. But in a funny way, the pragmatism isn't exactly a philosophy. The pragmatism is a kind of disposition for doing that work.

50:16 Stuart: That's right, yeah. In fact, these basic suppositions in the natural attitude or these hypotheses could be regarded as dispositions to behave in certain ways verbally and non verbally.

50:29 Mark: So I think a strict take on Kantianism would not admit of these Rortyan extensions of that, you know, that Kant.

50:36 Wes: Fuck.

50:37 Mark: The world of science is as objective as you're going to get. And so of course you could still doubt your specific models. But there is a truth of the matter of whether this theory or that theory is correct within that world. And you can hold that and hold a strong belief in, you know, natural kinds as accurately reflecting the ontology of the experience world of the scientific world and still have some metaphysical other realm.

51:04 Wes: Yeah. So for Kant, I think there is a truth of the matter as to whether there's a God. It's just that we can't know that.

51:11 Stuart: Yes.

51:12 Wes: And there are things in themselves. And Kant talks as if our empirical world is sort of causally related, even though, you know, importantly he thinks of causality as something that is our own part of our conceptual apparatus that we sort of imbue the world with. So whatever causality prime or, you know, put an asterisk next to it. But he talks, at least in places, as if there's some sort of other causality which relates us to things in themselves. Which means that whatever our conceptual categories and so on, there's a systematic relationship between the empirical world and things in themselves, which would suggest to us that we can't know that a horse is a natural kind in the strict sense.

Or we can't be naive realists. We might think there's a sort of veil over everything, the veil of appearance. But we could think that the appearances are systematically related to these mind independent realities. The realities themselves are unknowable, but they sort of anchor us.

52:14 Stuart: This is good. I use the expression modification of Kant's view and one could regard it as a rather drastic modification that I was suggesting.

52:24 Wes: Okay. To get to the Rortyan view.

52:26 Stuart: Yeah, yeah. And I don't really want to go where Rorty went.

52:31 Mark: Do you want to go where hegel went, we were talking about, you were leading a Hegel's logic group. And I'm wondering if that was just a philosophical curiosity, a challenge, or whether that has actually fed into your understanding, you know, at least lurking in the background of this book.

52:45 Stuart: I was interested in Hegel because he seems to have been someone who had a non analytic conception of wholeness. And I wanted to know whether it was necessarily obscure, that is whether Hegel's account could be clarified in a way that would meet the criteria of the ontological analyst or whether it could not be. And I concluded that it could not be. That was my interest.

53:18 Mark: That's three years to find that out.

53:19 Stuart: Yeah, I have a lot of patience for these things, for these tiny little questions. But back to Kant. He took it as a fact that there are necessary truths in the new physics, the new Newtonian physics. And there is some controversy in the literature as to just how Newtonian he was. But he did take it as a fact that there are these necessary truths in Newtonian physics. And he took it as a fact that there are necessary truths in Euclidean geometry. And his question was, how is that possible? One might try something analogous to what Kant did, but instead of using Newtonian physics, use Aristotelian physics.

One supposes, and I would introduce this as a hypothesis, not a mere assumption as a hypothesis that there are some necessary truths. And I'm going to be rather extreme here, there are some necessary truths in Aristotle's biology, not just in the book physics, but in his biological writings. And the question is, how is that possible? And one might be able to argue, I've never thought about this before and there are probably a number of very great problems in carrying out the project. But it might be possible to do in a way analogous to what Kant did with these propositions in Newton's physics, to show that they're possible only if there are genuine continuants and that they belong to specific natural kinds.

And then one would have a rather interesting pair of treatises. One could give this other one the title Critique of Pure Ratiocination, let's say, or A Critique of Nous or of Noesis. With these two, one would then have to compare and see, well, one is based on one sort of hypothesis, the other is based on another hypothesis, and one would have to see which one was acceptable. And I think there's a meta-Kantian position according to which it's not a matter of discovery, it's a matter ultimately of deciding. We just decide that this is the way now in saying we Just decide it doesn't mean it's arbitrary.

What we decide might be on the grounds that it's very useful in some way. We're very interested in this. For example, if our interest is like Descartes or Bacon's in mastering Nature, it might be that the new science is much more powerful for mastering nature than Aristotle's physics. And so one would prefer it on that ground.

56:08 Dylan: But what's interesting about that position is that you could imagine there being that decision depending upon what you were looking at and what you were trying to solve.

56:19 Stuart: Yep. So a lot depends on what questions we begin with and what problems we begin with.

56:24 Mark: I think Boethius started that treatise, the Critique of Ratiocination, but he was executed too fast.

56:30 Stuart: Yeah. Yeah. So it remains to be written. I won't, but go with it, Wes.

56:38 Mark: You can do it.

56:39 Stuart: I'm putting it out in this podcast as a project for someone to, to spend a few decades on.

56:45 Dylan: You wait, we'll get somebody emailing us a 200,000 word document.

56:51 Wes: It's happened before

56:55 Stuart: and I'm not putting it out there.

56:57 Mark: Well, we should have some sort of closing thoughts. I had asked Dylan, like, okay, well, you've looked at the book beforehand. What should we read before getting to this? Should we read Aristotle's categories? Should we read something else? And we even had Foucault on the order of things tentatively in here, which I don't know that would have helped particularly to understand it's that in particular. But I do definitely feel like this is like many kinds of modern philosophy, like Rorty's Philosophy and the Mirror of Nature that we read some of recently.

This is so historically reflective and action packed that we were sort of prepared. We've done Kripke, we've done De Anima, we've done various other things that made some of this make more sense. But we haven't even done a straight up one in the many episode. We haven't done Parmenides. There's so many other things that I feel like would have made us more competent to breeze through this book and be able to reflect back to our listeners. Oh yeah, just go back to those other things we've already talked about. So since in some ways this was a jumping ahead, it's another one of these things that presents a challenge for us of that.

Okay, what do we have to cover in the next years that will retroactively make all this. I don't want to say, make more sense. I think you're as clear as could be given the subject matter in the book and you certainly repeated yourself enough to remind us of what is at stake, you know. So I really admire the clarity with which you did go through the history and the different possible positions on these various issues and without getting lost in historical detail, just hear the arguments for and against, say, nominalism, about universals and, you know, those kind of things.

But I still did not feel up to the task of really understanding this enough to have opinions on whether you are right about almost any given thing in here. So it's a nice aspirational work for me.

58:50 Stuart: I thought the questions were great. I think you may be underestimating yourself.

58:54 Mark: Wes, what'd you think? Any last thoughts?

58:57 Wes: Yes. Thanks for coming on, Stewart. This was a pleasure.

59:01 Stuart: Thank you.

59:02 Wes: Pleasure.

59:02 Stuart: For me.

59:03 Wes: I also read Zetetic Skepticism. Was it? I think that was your first.

59:06 Stuart: I know you did.

59:08 Wes: How do you know that?

59:10 Stuart: Maybe it's on your website somewhere and I read it.

59:13 Wes: Yeah, I have mentioned.

59:15 Stuart: And you mentioned you in a few pieces. I was pleased. Thank you for reading it.

59:21 Mark: Do you have a Google Alert on yourself so you can see when anybody is talking about your work?

59:26 Stuart: No. I didn't even know there was such a thing.

59:29 Mark: Do it.

59:30 Wes: So I will say yes, this book was difficult and I knew given the amount of time I had to prepare, I wouldn't feel sufficiently prepared. It would take a very long time. But I think it's something that rewards. You know, I did have a chance to go through the parts that I was able to read all but chapter six and seven to go through and take notes. And it's certainly something that rewards rereading and thinking about. I was surprised that I felt like I understood the overall gist of the argument, let's say, by the end of that. But I have to say in the beginning I found it, yeah, very hard going, but very rewarding. So thank you. Thanks again.

1:00:10 Stuart: Well, thank you for those kind comments.

1:00:13 Mark: Dylan, wrap us up.

1:00:15 Dylan: You know, this kind of technicality and philosophy I always have a hard time with because I don't have as much training in philosophy as the other guys do, but I find myself really enjoying it. For me, the discussion of natural kinds and the natural law and then emergence is like the place that I most want to go. I am really, really interested in that account. And what I find both pleasing and somewhat discouraging is the combination of all the work that one has to do just in articulating the problem and the sort of landscape that Emergence sits in, which is really a big chunk of the book, right?

1:00:52 Stuart: Yes.

1:00:53 Dylan: If I think of it that way,

1:00:54 Stuart: the whole book could be regardless about that.

1:00:56 Dylan: Exactly. But in the end, it's so hard to say anything about the emergent stuff. And so it's both exciting and discouraging at the same time. Because I feel like the one piece that I particularly felt like I got a lot more clarity on was just that linking up that I mentioned earlier, that equation that you agreed with that natural laws plus emergence gives you natural kinds. And I guess I find myself even wanting to think about what it would mean to articulate it even more and wondering if it's just slippery in the way that we've talked about it, if there's a handle you can get on it better, or is it just a matter of treading over it many times in different ways?

And also whether or not there's a sort of a chapter nine that you have physical kinds and biological kinds, and if there is investigations into the world that you can parse out emergent things from non emergent things, that would give you a handle on that in a similar way that you get a handle on natural kinds by looking at the

1:02:01 Stuart: world treading the same ground over and over. Accords with my personal experience. I think that dealing with philosophical questions and problems of the sort I try to deal with in this book is a lot like bird watching. Let's say you get out there all the time, or you sit down, or however one thinks walking, however you just think about it over and over and these questions and problems become more and more familiar to you, just as birds become more and more familiar in bird watching. And sometimes you can make a breakthrough, or what seems like a breakthrough.

You finally understand something that you didn't understand before. But it's through just getting out there or sitting down, however one does it, and living with the problem for a long time. I don't know how idiosyncratic my experience is in this regard, but that's the way it's been for me. And in fact, it was when I was taking your faculty study group and quantum field theory that this equation, as you called it, finally occurred to me. Oh, toward the end we were reading those. It was just a few writings by reputable physicists saying that a theory of everything cannot possibly be a theory of everything thing.

They had arguments, and these arguments amounted pretty much to noting that we have these different sciences and nobody's been able to show that they can all be reduced to, let's say, quantum field theory or string theory or something like that. And that's not an airtight argument. It's not conclusive, but it's a reason for thinking that they might be right. And it's with the heterogeneity that comes as the universe cooled. Accepting the current theory for a moment, that continuants come into being. I think it was a breakthrough for me to see that there is actually a scientific reason for concluding that if there are any continuants at all, they have all emerged.

Yes. And they have emerged out of a quantum field situation in which there were no continuants. And some of these continuants apparently fall into rather clear cut kinds. So there's your equation, as you call it. Yeah. So that for me has the feel of a breakthrough. But it came after I think I've been thinking about the subject matter of this book since a seminar I gave almost the first year I started teaching about 1972, 73 and took me that long too well to realize this, if indeed I realized it and not just invented it.

1:04:43 Dylan: That study group was one of the best things that I ever did here. It was one of the most enjoyable things.

1:04:49 Stuart: It was good.

1:04:50 Wes: And I had Stewart for freshman language, I remember.

1:04:54 Stuart: And I was on the committee examining your senior. That's right, Yeah.

1:04:59 Wes: I wrote a thesis on the symposium. So yeah, yeah, I felt good that

1:05:03 Mark: I didn't feel unlike in Eva's work, that this was so like St. John's based in its methodology, that I was being excluded from something.

1:05:11 Stuart: No, I am. In my thinking, I've always been a marginal member of the St. John's community.

1:05:19 Mark: Next time we're going to be talking about Fyodor Dostoevsky's existentialist novel the Idiot, with guest Corey Mohler, who you probably know as the author of Existential Comics. If you're not familiar with that, check out existentialcomics.com our closing song is going to be Destroy the Box, an abstract improvisational jazz number from Werdyger, Cain and Gray from the 2014 album Organic Architecture. I interviewed David Cain and Paul Werdicko on the Nakedly examined music episode 30. To hear the interview and many other cool interviews that I've released recently there, check out nakedlyexaminedmusic.com folks should go on parcelexaminelife.com comment on what you think about this episode, on ideas you have for upcoming episodes, reach out to us.

Pel partiallyexaminedlife.com we always welcome your feedback. Follow us on Facebook, follow us on Twitter and go buy Stewart's book. Despite what I just said, I think you'll all immediately love will be as easy as butter.

1:06:16 Dylan: I reversed. We'll have a link to it on the website. Yes.

1:06:21 Mark: Good night, everybody.

1:06:22 Wes: Good night.

1:06:22 Stuart: Good. Sam. It.

1:07:20 Wes: Sa.